ZINC PROTECTION AGAINST CADMIUM-INDUCED DESTRUCTION OF THE MONOLAYER OF CULTURED VASCULAR ENDOTHELIAL-CELLS

The effect of zinc on the destruction of vascular endothelial cell monolayer caused by cadmium was investigated using bovine aortic endothelial cells in a culture system. It was histologically revealed that cadmium-induced de-endothelialized area formation was markedly prevented by zinc. Zinc prevented cadmium-induced detachment of [H-3]thymidine-labeled endothelial cells from the monolayer. Although cadmium increased the activity of lactate dehydrogenase in the medium, a marker of nonspecific cell damage, zinc markedly suppressed it. On the other hand, zinc significantly prevented cadmium-induced decrease in the incorporation of [H-3]thymidine into the acid-insoluble fraction of the growing cells. From these results, it was suggested that impairment of the endothelial cell monolayer caused by cadmium is protected by zinc; this protection was postulated to be due to both a reduction of the cell detachment caused by cadmium-induced nonspecific cell damage and a decrease in cadmium inhibition of the cell proliferation which would help the repair of de-endothelialized areas.